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Rotor/break pad clean hints?

by adam900710
Sat, Aug 29, 2015 12:34
10

Hi all,

After a ride in heavy rain, I feel my front brake power drops a lot, it was quite good for 2 months and yes, it's hydro disc brake (RS685 STI + RS785 caliper with RS81 160mm rotor).

And after than ride in rain, now front brake makes a horrible noise when it's going to a stop. And for brake power, it's almost worse than my 6800 rim brake.
The rear brake didn't change even a bit.(140mm RT81 rotor BTW)

Although I did clean the bike almost immediately after the ride in rain, I didn't do anything special for front brake.

So I think I need to do something with the rotor and the brake pads.
I only have muc-off bio drivetrain cleaner(yes, that yellow grean liquid), can I use it on rotor/pads?
Or I need something special to clean the rotor/pad?
BTW, the brake and rotor was brought about 2 months ago, so I don't think it's wear out problem.

Thanks
Adam

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10 comments

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hampstead_bandit | 8 years ago
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Don't put brake pads in the oven, it damages the binding resin used to bond the pad material together 3

Regularly cleaning with bicycle (not automotive) disc brake cleaner is a sensible idea, and not using aerosol lubricants on the chain, or aerosol polishes directly on the bike (spray into a cloth and wipe) as over spray can easily contaminate the rotor and pads.

Rotors can be easily cleaned even when badly contaminated, we'd normally use Isopropyl Alcohol and clean, lint free cloths.

Once pads are contaminated, they are usually for the bin, and a brand new set will be fitted once the rotor and caliper bay have been degreased.

Disc brake cleaner will actually eliminate many operating noises such as squealing and even juddering (as long as caliper is properly centred over rotor).

Be aware some frames (typically full suspension) can suffer from strange noises caused by harmonic frequencies (combinations of frame / brake / rotor/???), these are often cured by a switch to organic pads from original sintered metal pads.

I'd advise dosing the rotor and spraying the pads through the back of the caliper pad bay, then wiping off excess with a clean cloth, and the real trick is to immediately ride the bike up and down a quiet road with ever increasing hard braking.

The bike will normally squeal extremely loudly for the first 10-15 stops, once its quietened down you are good to go, you will see then see a dramatic increase in leverage (stopping power)

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joemmo | 8 years ago
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If the squealing persists put a thin coating of copper slip grease on the back of the pad, it can help reduce the noise.

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mike the bike | 8 years ago
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I have heard of people putting their contaminated brake pads in a low oven for a few minutes to burn off oil.
I have no idea if it works well, but it is free.

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Welsh boy replied to mike the bike | 8 years ago
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mike the bike wrote:

I have heard of people putting their contaminated brake pads in a low oven for a few minutes to burn off oil.

I have also heard of people wrestling with alligators, doesn't make it a good idea though! Brake pads are not porous so give them a good clean with IPA or lighter fuel and take any glaze off them by lightly rubbing over a flat sheet of wet and dry paper or emery paper, that usually works.

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adam900710 | 8 years ago
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Miracle happened!!!!!

I was going to give up and ready to order a new pair of pads torrmor, but before that, I tried to apply degreaser on pads and rotor, waited for about 3 minutes.

Then rub the pad with the other for 1 minute, and wash both roter and pads with water.

Dry them and reinstall.

Suddenly, the noise is gone!!
However the brake power is not at its best yet.

I'll ride for tens of kilos to see what will happen then.

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adam900710 | 8 years ago
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Thanks a lot.

Seems I'd better order a new pair of pads now...

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kev-s | 8 years ago
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You need to give the caliper and disc a good clean with rubbing/isopropyl alcohol

Also if the pads are contaminated then try giving them a light sanding and you may be lucky, if not then new pads will be needed

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adam900710 | 8 years ago
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Checked the pads.
And, it seems to be some oil 20

But not the worst case like breaking piston, it's the oil at the caliper bleed port that I forgot to clean one or two months ago.

Now, what to do?
Will degreaser help in these case?

Avatar
adam900710 | 8 years ago
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I'll check it, but will it get worn in just 2 months?

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2 Wheeled Idiot | 8 years ago
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Check your brake pad
Sounds like they're worn through.

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